Gabor - I felt like many of your questions deserved their own response, so I'm going to send a few emails in a row addressing various questions you pose. First, this:
Could you give use cases where a clever Matlab user would run a perl script > to solve a problem more easily or faster than with standar Matlab tools? > By clever Matlab user do you mean clever Perl user? Or clever Matlab user? I think a clever Matlab user could write a Perl script to digest a bunch of data and spit-out a csv file that Matlab could easily read and process. I can't speak from experience on this one. Here's an example of how switching to PDL made my life easier, which I think addresses your prompt. When in the lab, I take two signals of voltage vs time. The first signal comes from an accelerometer and basically tells me how my system is behaving - its the data I'm really interested in analyzing. The second signal comes from the power supply, which really ought to be constant over the course of a single measurement. When working in Matlab, I would save both signals into a single ASCII file. The filenames were based on the voltages that the power supply said it was supplying to the system. When I analyzed the data using Matlab, I would create string cell-arrays with all of the filenames I wanted to analyze because I couldn't think of an easier way to analyze only a subset of the data. Then I discovered PDL. I installed ActiveState Perl on my data-aquisition system and wrote a small Perl script that repeatedly scanned a directory for new files. I decided to save the voltage supply and the system response in two different files. When the script found a new pair of files, it would analyze the voltage signal and compute the mean and standard deviation of the data, and rename the system-response data with a fully descriptive filename: 'Motor05,0.462+-4.65e-4.dat'. This made my life much easier becuase I didn't even have to pay close attention to my power supply anymore to get the right filename. I just saved the files under something like 'a_1.dat' and 'a_2.dat' and the perl script did the renaming for me. Later, I learned that the power supply occasionally exhibited jumps in what it supplied to my system, and finding bad data sets simply amounted to identifying large error bars, which were already part of the fiile name. Could I have done this using Matlab? (1) No, because I didin't have a license for Matlab on that computer. (2) No, because the thought of having a Matlab script running in the background doing that file processing for me never would have occurred to me. Implementing a Matlab solution that works the way I think is not impossible, but it has too many barriers. David
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